The Book of Gelel contains all secrets of the Stone of Gelel and how to control its power, along with the history of Temujin's people and the developments they attained with the aid of the Stone's power. The Book of Gelel tells the story of how the power of Gelel came to be discovered and used by Temujin's ancestors. The book followed Temujin's ancestors over the sea and later came into the possession of Haido (claiming he bought it from a travelling merchant, to which Kahiko doubted it was so simple) who started to use its secrets for evil purposes. The book is lost when it was left aboard Haido's airship, which was sucked into the Space–Time Path.